Then don't start putting things away before you close. That guy was a dick for doing that, but still... Do you remember back in school when the teachers would get so pissed for people packing up 5 minutes before class would end?

this may come as something new but shit that happened in school like the example you mentioned doesn't translate well to the real world. Bosses usually have a time they want employees out of the business when it closes so employees have to start putting shit away early to make that deadline and if they don't make the time they can get in trouble.